如何发现Python Fabric中的当前角色 [英] How to discover current role in Python Fabric

问题描述

这是一个非常 Fabric 的特定问题，但是经验丰富的python黑客也许可以回答这个问题，即使他们不知道面料.

This is a very Fabric specific question, but more experienced python hackers might be able to answer this, even if they don't know Fabric.

我正在尝试在命令中指定不同的行为，具体取决于它运行的角色，即:

I am trying to specify different behaviour in a command depending on which role it is running for, i.e.:

def restart():
    if (SERVERTYPE == "APACHE"):
        sudo("apache2ctl graceful",pty=True)
    elif (SERVERTYPE == "APE"):
        sudo("supervisorctl reload",pty=True)

我正在用类似这样的功能来破解它:

I was hacking this with functions like this one:

def apache():
    global SERVERTYPE
    SERVERTYPE = "APACHE"
    env.hosts = ['xxx.xxx.com']

但这显然不是很优雅，我只是发现了角色，所以我的问题是:

But that is obviously not very elegant and I just discovered roles, so my question is:

如何确定当前实例属于哪个角色?

How do I figure out which role a current instance belongs to?

env.roledefs = {
    'apache': ['xxx.xxx.com'],
    'APE': ['yyy.xxx.com'],
}

谢谢！

推荐答案

更新:刚刚选中

Update: Just checked the source code and it seems that this was already available as early as 1.4.2!

更新2 :使用@roles装饰器(在1.5.3中)似乎不能正常工作！仅当使用-R命令行标志指定角色时，它才起作用.

update 2: This seems not to work when using the @roles decorator (in 1.5.3)! It only works when specifying the roles using the -R command line flag.

对于结构1.5.3，当前角色可直接在"fabric.api.env.roles"中获得.例如:

For fabric 1.5.3 the current roles are directly available in `fabric.api.env.roles'. For example:

import fabric.api as fab

fab.env.roledefs['staging'] = ['bbs-evolution.ipsw.dt.ept.lu']
fab.env.roledefs['prod'] = ['bbs-arbiter.ipsw.dt.ept.lu']


@fab.task
def testrole():
    print fab.env.roles

在控制台上测试输出:

› fab -R staging testrole
[bbs-evolution.ipsw.dt.ept.lu] Executing task 'testrole'
['staging']

Done.

或者:

› fab -R staging,prod testrole
[bbs-evolution.ipsw.dt.ept.lu] Executing task 'testrole'
['staging', 'prod']
[bbs-arbiter.ipsw.dt.ept.lu] Executing task 'testrole'
['staging', 'prod']

Done.

有了这个，我们可以在结构任务中做一个简单的in测试:

With this, we can do a simple in test in a fabric task:

@fab.task
def testrole():
    if 'prod' in fab.env.roles:
        do_production_stuff()
    elif 'staging' in fab.env.roles:
        do_staging_stuff()
    else:
        raise ValueError('No valid role specified!')

这篇关于如何发现Python Fabric中的当前角色的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！